LEAP applies cutting-edge approaches in experimental evolution, ecology, and metagenomics to allow us to rigorously test how communities respond to environmental change.
When species experience changes in environmental conditions, they can undergo a decline in their population sizes. The ability of species to persist under the new environmental conditions depends on their adaptive capacity. Evolutionary rescue happens when adaptation occurs and restores positive growth to previously declining populations. Connectivity also plays an important role in promoting evolutionary rescue by allowing for gene flow between populations.
LEAP is an array of at least 96 cattle tanks, each containing 1000 liters of unfiltered water, piped directly from Lake Hertel, located over a kilometer away. The plumbing allows for a semi-continuous flow of lake water into and out of the tanks thoughout the field season.
This set-up (called freshwater mesocosms) can capture elements of natural freshwater ponds and lakes, allowing us to explore the future of our freshwater ecosystems.
The use of pesticides, like glyphosate and neonicotinoid insecticides, is widespread in Canada and globally, and may be causing rapid biodiversity change. We want to understand the impact of pestices on freshwater communities, and communities’ abilities to adapt to pesticides.
When communities are exposed to non-lethal environmental stressors over several generations, they may be able to develop community-level stress tolerance. We test whether prolonged prior exposure to an environmental stressor can induce tolerance to subsequent increased stress.
Rescue interacts with trophic structure (who eats who) because the stress experienced by one species may also be experienced by its predators and prey. We study the sensitivity of trophic levels to environmental stress, and which trophic levels contribute mostly to evolutionary rescue.
We show that community biomass may exhibit resistance to pestice application when tolerant species are able to compensate for the biomass lost with the most sensitive species. However, pesticide application led to species extinction and a long-lasting change to the community structure.
Our work suggests that a history of exposure to an environmental stressor may increase future resistance or stress tolerance, but it comes at the cost of resilience - the ability of the community to bouce back as quickly as a community that was not pre-exposed to the environmental stressor.
We found that predators show greater sensitivity to environmental stress than their prey. When predators became extinct, their prey underwent evolutionary rescue. Our results suggest that in a predator-prey community, prey evolutionary rescue is conditional on release from predation.
The future quality of our freshwater ecosystems, their biodiversity and the ecosystem services they provide depends upon how they adapt to climate change, and to the growing pressures from agriculture, pollution and urbanization.
